Pius IX began as a liberal pope and became the opposite. Revolution drove him from Rome in 1848. He then turned firmly against modern ideas. His council declared papal infallibility in 1870. In the same year Italian troops took Rome. That ended a thousand years of papal rule over the city. He called himself a prisoner in the Vatican. He was later beatified, though his reign remains controversial. His long papacy left the church more centralised than before.
Key Milestones
1846: Elected pope
1854: Defines the Immaculate Conception
1869: Opens the First Vatican Council
1870: Loses Rome to Italy
Pope Pius IX (Italian: Pio IX; born Giovanni Maria Battista Pietro Pellegrino Isidoro Mastai-Ferretti; 13 May 1792 – 7 February 1878) was head of the Catholic Church from 16 June 1846 until his death in February 1878.